The present disclosure relates to a coating material formed by a ternary phase of hafnium boron and carbon, which can be deposited on surfaces of components and tools for improving their performance. The present disclosure relates furthermore to a method for producing this coating material.
The use of metal boron carbide materials as coating as well as the production of this kind of coating by using physical vapour deposition (PVD) techniques is well known from the state of the art.
In the theoretical “Systematic study on the electronic structure and mechanical properties of X2BC (X=Mo, Ti, V, Zr, Nb, Hf, Ta and W)” published in J. Phys.: Condens. Matter 25 (2013) 045501 (6pp), it was reported that Mo2BC-type phases were investigated by using quantum mechanics calculations for predicting properties in case Mo was replaced by other transitional metals, such as Ti, V, Zr, Nb, Hf, Ta or W. According to the calculations a higher level of ductility is expected for higher values of valence electron concentration (VEC), as inferred from both the more positive Cauchy pressure and the larger value of the bulk to shear modulus ratio (B/G). As conclusion of this study, it was indicated that this rather unusual combination of high stiffness and moderate ductility renders X2BC compounds with X=Ta, Mo and W as promising candidates for protection of cutting and forming tools.
WO2014053209A1 discloses for example a method for producing metal boron carbide coatings by using pulsed PVD processes. In particular, WO2014053209A1 suggests use of high-power impulse magnetron sputtering (HiPIMS) technique, whereby very high current and correspondingly, power densities must be applied as impulses. In this manner, it was possible to form microcrystalline phases of metal boron carbides; more specifically Mo2BC at temperatures below 600° C., which could otherwise only be synthesized by conventional dc magnetron sputtering at substrate temperatures above 600° C. WO2014053209A1 discloses furthermore that metal boron carbides formed from transition metals such as Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W should be particularly suitable for attaining good wear resistance or low friction coefficients. However not all of these possibly suitable metal boron carbides are available or can be produced, until now.
Moreover, the previously depicted method for producing metal boron carbide coatings by means of HiPIMS techniques is normally expensive and complex. Also, the proposed microcrystalline Mo2BC coatings exhibit in addition to their microcrystalline phase a significant amount of amorphous and/or nanocrystalline phases. This physical nature of the known microcrystalline Mo2BC coatings limits the industrial use of them because the mechanical and thermal properties of such materials are often governed by the properties of the amorphous and/or nanocrystalline grain boundary phase.
The previously depicted drawbacks known from the state of the art imply that a metal boron carbide, being able to suit the high demands in industrial applications with excellent mechanical properties, should exhibit essentially a single phase crystalline structure.
The foregoing examples of the related art and limitations therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.